1. Field of the Invention
The present invention relates to an edge emphasizing circuit. More specifically, the present invention relates to an edge emphasizing circuit which is applied to a digital camera, for example, and produces an edge emphasizing signal by performing weighing addition with respect to a first pixel signal output from an imager and a second pixel signal obtained by performing a filtering process on the first pixel signal.
2. Description of the Prior Art
As one image processing technique in a digital camera, there is an edge emphasizing for emphasizing an edge portion of an image. This is a technique that an edge (high-frequency) component of an image signal output from an image sensor is extracted, and an aperture signal is produced by applying an aperture gain to the extracted edge component and superimposed on the image signal. For the purpose of extracting the edge component in such the edge emphasizing, conventionally, the image signal is directly subjected to an edge extracting process.
However, in the above-described prior art, in a case a relatively high-frequency noise component is included in the image signal, the noise component is also extracted together with the edge component. Consequently, there is a problem that since the aperture gain is also applied to the extracted noise component, not only the edge component but also the noise component is emphasized, and therefore, an image quality is deteriorated.